Death Valley geology field trip

Golden Canyon stop 3

Park interpreter Mark Neuweld points out ancient alluvial fan deposits of the Furnace Creek Formation. The mixture of boulders surrounded by finer grains is a typical texture seen in modern alluvial fan deposits.

Ancient Alluvial Fans

Look closely at the rock exposed in the canyon walls. Notice that the
layers are composed of rocky debris that ranges in size from boulders
to fine-grained sand and silt. Where have you seen similar sediment?
These layers of poorly sorted conglomerate were deposited six million
years ago on an ancient alluvial fan. The loose material was subsequently
buried and cemented into solid rock known as the Furnace Creek Formation.
More recent uplift and erosion have exposed them to view.

At the time that these rock layers were being deposited,
Golden Canyon and the modern basin of Death Valley
had not yet formed. What was the source for the material
that composes these ancient alluvial
fans? These layers of conglomerate become thinner and
disappear further to the east. The type of rock material
that composes these conglomerates
also indicates that the sediment came from the west.
It's thought
that the source was part of the bedrock of the Panamint
Mountains; the modern counterparts of the ancient fans you are looking
at are the gigantic
fans of the Panamint Mountains that you observed from
the mouth of Golden Canyon.

The narrow, deep shape of the side canyons of Death
Valley indicate that the uplift of the mountains
is relatively recent, consistent with other evidence that the landscape
of Death Valley is
quite young. These relatively rare flood events are
so dramatic that their effects can even be noticed
within the brief span
of a human lifetime.
Such geologic forces have been carving the canyons
of Death Valley for millions of years, constantly
sculpting and changing this desert landscape.